Long-lasting effect of early handling on the peripheral benzodiazepine receptor.

The present study determined the impact of early handling (EH) in rats on behavioral response to environmental stress and on peripheral benzodiazepine receptor (PBR) binding characteristics (Bmax and Kd) in various organs. The behavioral consequences of EH in rats were expressed as increased exploratory activity in an open-field paradigm, when compared with nonhandled control rats. These findings are interpreted in terms of decreased emotionality. The biochemical consequences of EH, in both male and female rats, were expressed as the upregulation of PBR in the adrenal and kidney and the downregulation of gonadal (testis and ovary) PBR. It is possible that the long-lasting adrenal and renal changes in PBR expression in EH rats may enable better regulation of the hypothalamic-pituitary-adrenal axis, renin-angiotensin system, and autonomic nervous system responses to stress in adulthood. The significance of the EH-induced reduction in gonadal PBR for gonadal activity in adulthood is as yet unclear.

The Bird's Nest inferior vena caval filter: review of a single-center experience.

PURPOSE: To examine a large single-center experience with Bird's Nest vena caval filters for indications, clinically evident recurrent thromboembolic disease, and other filter-related complications. MATERIALS AND METHODS: During a 6-year period, 308 patients underwent percutaneous placement of an inferior vena caval filter. The 267 patients who received a Bird's Nest filter are the subject of this retrospective review. The series included 162 men and 105 women who ranged in age from 16 to 88 years (mean, 57.1 +/- 17.0 standard deviation). RESULTS: Indications for filter placement included contraindication to anticoagulation (n = 141), complication of anticoagulation (n = 23), failure of anticoagulation (n = 30), failure of previously placed filter (n = 1), and prophylaxis (n = 82). Ten patients had more than one indication. Acute lower extremity deep venous thrombosis was confirmed in 133 patients, pulmonary embolism (PE) was found in 44 patients, and both were positively diagnosed in 37 other patients. Fifty-three patients had no documented acute thromboembolic disease at the time of insertion. Mean follow-up was 13 months. Thirty-day mortality was 9.7%, including one death from recurrent PE and one major puncture-site bleeding episode that may have contributed to death. Recurrent PE was found at radionuclide scanning or autopsy in three patients (1.1%), whereas another eight patients (3.0%) had suspected recurrent PE without confirmatory studies. Eight patients (3.0%) developed early venous access site thrombosis, including two who progressed to phlegmasia cerulea dolens with fatal complications. Significant nonthromboembolic problems were encountered in 1.9% of patients. CONCLUSIONS: The Bird's Nest filter is a safe and effective device for patients with complicated venous thromboembolic disease.

A behavioral model of excitotoxicity: retinal degeneration, loss of vision, and subsequent recovery after intraocular NMDA administration in adult rats.

To establish a new behavioral animal model of excitotoxicity, we injected adult rats intraocularly with a single dose of 2, 20, or 100 nmol of N-methyl-D-aspartate (NMDA). We quantified visual impairment by plotting the size of the visual field in which the rats successfully oriented towards a small, moving target. In comparison to the saline-injected (contralateral) control side, the side injected with 2 nmol of NMDA was not significantly impaired. When injected with higher doses, the rats were nearly blind immediately after surgery, with only about 20% (20 nmol NMDA) or 10% (100 nmol NMDA) of residual vision. Within about 3 weeks, however, visual performance returned to near-normal levels. Simultaneous intraocular administration of a non-competitive NMDA-antagonist, MK-801 (1 nmol), resulted in complete behavioral protection. NMDA administration led to a dose-dependent loss of cells within the ganglion cell layer, as assessed in whole-mounted retinae which were retrogradely labelled with horseradish peroxidase (HRP). Whereas 2 nmol of NMDA led to the loss of about 30% of retinal ganglion cells (RGCs), at higher NMDA doses only 13% of the RGCs survived. After the injection of 20 nmol of NMDA, large-diameter RGCs (> 22 microns) survived the lesion to a greater extent than small diameter cells (8-21 microns); at 100 nmol cells of all diameters were equally affected. The number of Nissl-stained cells with small diameters (< 11 microns), presumed to be displaced amacrine cells, was also affected by NMDA, although to a lesser degree. Analysis of behavioral performance (vision score) and the number of cells in the retina revealed a correlation of r = 0.76 between visual performance and the number of HRP-filled RGCs immediately after surgery. Lower correlations were found between visual performance and cells stained with Nissl of diameters smaller than 11 microns (presumed RGCs without retinofugal connections; r = 0.55 and r = 0.58, respectively). Because of the spontaneous recovery of vision, all correlations declined to values near 0 after 3 weeks. Thus, despite a dramatic loss of RGCs following NMDA administration, visual deficits recover significantly in adult rats within 2-3 weeks.